The vast majority of Olympic-themed websites are fakes, set up to either scam or spam visitors, according to new research.

The research, carried out by security firm Zscaler, looked at every domain name containing the word "Olympics" which had been accessed over the course of one day. Zscaler claims that 80% of all the Olympic-related websites it examined are fake, set up to either redirect traffic to certain pages for advertising reasons or to scam users out of money.

Zscaler says the most common form of scam was typo-squatting. This is when a website with a similar address to a more famous site is set up, hoping to lure visitors who spell the name of their intended destination incorrectly. In this case it is US Olympic broadcaster NBC that is the target.

Some of the fake sites set up by the scammers include cnbcolympics.com, which contains and additional ‘c’, nbcolympic.com, which is missing the ‘s’ at the end, and ncbolympics.com, which has the ‘c’ and the ‘b’ swapped.

These fake sites are swamped with advertising. The aim is to get visitors to click the advertising links as there is no useful information or content on the site. Whoever set up the site will then receive revenue from the ad links.

Zscaler points out that as domains cost so little money these days, this can be a cost-effective way for scammers to make money.

A similar scam is what Zscaler is calling "Made of Adsense" sites. These are highly-targeted sites that will always appear high up in Google’s rankings. These sites are also flooded with adverts, which users are encouraged to click on to get more content.

Finally are the sites that are set up to trick people into thinking they can watching the Olympic Games live and in real-time online for a low fee.

"Numerous pages, mostly parked on free hosting sites are created to redirect users to the TV scams. These redirection pages may be designed as reviews from users promoting the scam, or simple HTTP redirection scripts with no content actually displayed to the victim," Zscaler’s Julien Sobrier wrote on the company’s blog.

"I guess the good news is that most of the scams are targeting ‘low hanging fruit’ and don’t involve sophisticated exploits," Sobrier wrote.